The problem of pain in lupus: an explication of the role of biopsychosocial mechanisms.

Objective To define biopsychosocial mechanisms of pain that go above and beyond disease activity and organ damage in systemic lupus erythematosus (SLE). Methods We conducted a cross-sectional analysis of patient-reported data in a population-based registry of 766 people with SLE. Predictors of pain intensity and interference were examined using hierarchical linear regression. We built two main hierarchical regression models: pain intensity regressed on disease activity and organ damage; and pain interference regressed on disease activity and organ damage. For each model, we sought to establish the relationship between pain outcomes and the primary exposures using sequential steps comprising the inclusion of each construct in six stages: demographic, socioeconomic, physical, psychological, behavioral and social factors. We also conducted sensivity analyses eliminating all overt aspects of pain in the disease activity measure and reestimated the models. Results Disease activity and organ damage explained 32-33% of the variance in pain intensity and interference. Sociodemographic factors accounted for an additional 4-9% of variance in pain outcomes, while psychosocial/behavioral factors accounted for the final 4% of variance. In the sensitivity analyses, we found that disease activity and organ damage explained 25% of the variance in pain outcomes. Conclusion Disease activity only explained 33% of the variance of pain outcomes. However, there was an attenuation in these associations after accounting for psychosocial/behavioral factors, highlighting their roles in modifying the relationship between disease activity and pain. These findings suggest that multilevel interventions may be needed to tackle the negative impact of pain in SLE.